This invention relates to heavy duty vehicular steering column assemblies of the type incorporating telescoping steering shafts supported in sleeves. More particularly, this invention relates to bearing liners employed in the interface between steering shaft and sleeve members.
Bearing liners have evolved significantly from the old bronze and babbitt days. In fact, the loads and conditions under which current day truck and off-highway steering column assemblies must operate are more severe than ever. New materials, particularly synthetics, which either minimize the need for lubrication or avoid such need altogether, are now employed with great success. There remain, however, several aspects of steering assembly design in need of improvement.
For example, some anti-backlash mechanisms of today's bearing liners tend to be undependable over the useful life of steering assemblies, particularly when subjected to relatively high stress conditions. Other anti-backlash designs are too closely toleranced to permit adequate flexibility or sufficient freedom in the axial or telescoping movement of the steering members. Still other designs do not permit adequate play, and often result in high frictional losses in operation. Finally, it is desirable that an improved bearing liner, for use in a heavy truck steering assembly subjected to hydraulic pressures on the order of 3000 psi, be fabricated of a simple one-piece or unitary structure.